Water-assisted stable dispersal of graphene oxide in non-dispersible solvents and skin formation on the GO dispersion

Graphene oxide (GO) particles disperse well in a few polar solvents including water but do not disperse in non-polar and low dielectric constant solvents. The limitation of available solvents can restrict the application of GO compositional materials. Herein, we report that by adding small amount of water in a water-miscible solvent, the dispersity of GO can be significantly improved. The scheme works even in solvent with low dielectric constant; the water-added dioxane exhibited even better GO dispersity than pure water that is known to be the best solvent for GO dispersion to date. The method increases the spectrum of available solvents for dispersing GO particles. We also report a formation of skin layer with random birefringent wrinkles on the surface of water-dioxane binary GO dispersion. The skin layer in gel phase was partially stretchable and less rigid as compared to a fully dried GO film.